The present invention relates to endoscopes (including devices such as borescopes, fiberscopes, etc.) and specifically to variable direction-of-view and stereo viewing endoscopic devices.
Endoscopes are elongated devices used to visualize the inside of cavities. They are commonly utilized for medical and industrial applications. There has been a long felt need for endoscopes capable of varying their direction-of-view.
Most rigid endoscopes capable of varying their direction of view have a window that limits their scanning range. U.S. Pat. No. 4,697,577 to Forkner (1987) discloses a swing prism type of endoscope with a direction-of-view variable between 30 and 70 degrees from forward. WIPO publication WO 01/22865 by Ramsbottom (2001) discloses a similar device for varying the direction of view between 0 and 120 degrees. These two examples demonstrate an additional shortcoming of existing swing prism endoscopes: they only view on one side of the shaft axis. Other types of variable direction-of-view endoscopes, such as that disclosed in U.S. Pat. No. 5,762,603 to Thompson, have similar limitations.
An apparatus intended to solve these problems was disclosed in WIPO publication WO 99/42028 by Hoeg et al. (1999). This endoscope features a retractable rotatable housing that can protrude beyond the outer diameter of the endoscope shaft. The housing has a window that moves with the viewing direction. This design is unnecessarily complex and has potential sealing, electrical, and mechanical problems. Consequently this design has never been implemented, and therefore all the variable direction-of-view endoscopes heretofore known suffer from a number of disadvantages, including:
a) A generally limited direction-of-view range, which restricts viewing freedom and does not allow the user to look directly backwards, a feature that would be useful in many situations.
b) A limited view of the region directly in front of the endoscope, making it difficult to investigate the targeted area due to the user being unable view alternate sides of the shaft axis without rotating the endoscope.
c) Only one unique viewpoint for each particular view due to the fact that there are no redundant viewing configurations, resulting in the user having no alternative to an unfavorable viewpoint.
d) Difficult interpretation of depth in the view, as existing variable direction-of-view endoscopes do not provide a way to accomplish three-dimensional viewing.
From the discussion above, it should become apparent that there is a need for a variable direction-of-view endoscope that will provide an increased or unlimited scanning range which gives the user increased viewing freedom and backwards viewing capability; provide a swing-through-center capability by centering the direction of view range on the forward direction; provide redundant viewing capability such that each particular view direction can be obtained from multiple unique viewpoints; and provide the user with three-dimensional imaging to ease the interpretation of depth in the view.
In accordance with the present invention, a variable direction-of-view endoscope comprises an adjustable imaging system and a symmetric viewing window. The imaging system includes a pivotable optical component. The device features redundant viewing configurations that can be switched between using a simple flipping process. Additional steps to provide the user with three-dimensional viewing are also disclosed. The term xe2x80x9cendoscopexe2x80x9d as used herein is defined as an endoscope used for medical procedures, a borescope, a fiberscope, etc.
What is claimed is an apparatus for use as an endoscope, comprising a generally tubular member having a distal end portion, a proximal end portion, and a longitudinal axis; a viewing system, comprising a pivotable view vector originating from said distal end portion, wherein said pivotable view vector has a pivot axis that is not parallel to either said pivotable view vector or said longitudinal axis; a viewing window attached to said distal end portion, wherein said viewing window comprises a transparent viewing area about a symmetry plane, wherein said symmetry plane is generally parallel to both said pivot axis and said longitudinal axis near said distal end portion, and wherein said pivotable view vector passes through said transparent viewing area; a means for controllably rotating said distal end portion about said longitudinal axis; and a means for controllably rotating said pivotable view vector about said pivot axis.